JPS6369072A - Directory format - Google Patents

Abstract

PURPOSE:To logically erase a file in a simple way by recording that a file is erased, at a desired area in a head track number part at the directory of the information recording medium which cannot be erased but is capable of added recording only. CONSTITUTION:Bits from a bit phi of a head track part 22 of a directory format up to a bit 14 are used as a head track number recording area 22a, and a bit 15 is made into a erasing bit 22b to judge whether or not a file is already erased. When all directories are read, a bit 22b of respective directories is inspected, and it is assumed that a directory, for which the bit 22b is already erased is erased. At this time, when the same file name and an extender are present, the bit 22b of a final directory judges whether a file is erased or not. Consequently, the file can be easily erased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a directory format, and particularly to a directory format of a directory in which file information regarding file data recorded on an information track is recorded.

[Prior Art] Directories are used as a file management method for handling large amounts of file data on floppy disks, magnetic hard disks, and the like.

This is used as a heading for the file data, and includes the file name, creation date, writing position fa (first track number) 1 of the corresponding file data, and the like. File data can be easily managed by creating a new directory when new file data is created, and deleting the corresponding directory when unnecessary file data is generated.

[Problems to be solved by the invention] Erasing and rewriting are easy in systems using information recording media that can be erased and rewritten, such as the above-mentioned magnetic recording medium. However, in a system using an information recording medium such as an optical card, which allows only additional recording, it is difficult to erase files that are no longer needed.

[Means for solving the problem] The above problem is solved by adding an area indicating a logical deletion file to the first track number section in the directory in which file information about file data recorded on the information track is recorded. The problem is solved by the directory format of the present invention, which is characterized in that:

Here, the logically deleted file refers to a file that is actually recorded on the information track but is considered to have been deleted by the directory.

[Operation] The present invention attempts to perform an erasing operation by recording the file actually recorded on the information track as the erased file in a desired area within the first track number section of the directory. be.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

As an example of the directory format of the present invention, a directory format used for the directory of an optical card will be described.

FIG. 5 is a schematic diagram of an example of an optical card having a directory.

As shown in the figure, the optical card 30 has an information track 31
(311, 312, 3) and directory 32 (3
21, 322, -ψ・). The file data recorded on the information track 31 is recorded in the directory 32 for each file.

FIG. 2 is a schematic diagram showing an example of the structure of a directory format.

As shown in the figure, the structure of the directory 20 is a file base 25. Extension section 24. Attribute section 23° First track number section 22. It is composed of a file size section 21 and the like.

The characteristic part of the directory format of the present invention is in the first track number section 22.

FIG. 1 is a schematic diagram showing an embodiment of the first track number section according to the present invention.

As shown in the figure, bit φ to bit 14 are used as the leading track number recording area 22a, and bit 1
5 to the delete pin (22b) that determines whether the file has been deleted.

A file management method using the above directory format will be described below.

For example, assuming that DeletePicture 22b is 0 indicating a valid file and 1 indicating a deleted file, when the entire directory is read, the file name and extension will be changed as shown in FIG. 3(A). JIRO, DAT
, JIRO.

Directory 2 with names DOC, JIRO, DAT
Suppose there are three numbers 6, 27, and 28. Check the delete bit 22b for each directory 26 (file name and extension JIRO).

DAT), even if the delete bit is 0, the directory 28 (file name and extension J IRO, DA
If the delete bit of T) is 1, J I RO, D
The AT file is considered to have been deleted, and the usable file is stored in the JIRO, D as shown in Figure 3 (B).
Only OC will be available. At this time, the first track number of the directory 26 is the same as the first track number of the directory 28.

Following Figure 3 (A) above, the file name and extension JI
Add the RO and DAT files and save them to directory 2.
9 will be provided. In this additional recording, the value of the first track number is the directory 26 (file name and extension J
Since it is different from IRO, DAT), additionally recorded J
IRO.

It becomes possible to enable only DAT files.

The case of the above-mentioned additional recording will be specifically illustrated using FIG.

In Figure 4, the JIRO and DAT files (hereinafter referred to as J
IRO, DAT-1) was recorded from the 3rd track, and JIRO was newly added.

DAT file (hereinafter referred to as JIRO, DAT-2)
is recorded from the 8th track, JIRO,D
The value of the track number part 26a of the directory 26 of AT-1 is 0003 (hexadecimal), and the value of the track number part 28a of the directory 28 of JIRO, DAT-1 is 8003.
(hexadecimal number), the track number part 29a of the added JIRO, DAT-2 directory 29 is 000B (16
).

As explained above, the above directory format allows write-once information recording media to be handled in the same way as floppy disks.

In the above embodiment, the first track number is expressed as 2 bytes, but it can also be expressed as 1 byte.

Alternatively, it may be 3 bytes or more.

[Effects of the Invention] As explained in detail above, according to the directory format according to the present invention, by providing an area indicating a logical erase file in the first track number section, files can be easily deleted even on write-once information recording media. Logical deletion is now possible.

According to the present invention, by providing a special processing routine that is different from normal directory processing, it becomes possible to read logically erased files, and it becomes possible to take backups in file processing.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the first track number section according to the present invention. FIG. 2 is a schematic diagram showing an example of the structure of a directory format. FIGS. 3 and 4 are explanatory diagrams of the effects of the directory format of the present invention. FIG. 5 is a schematic diagram of an example of an optical card having a directory. 20・φ・・−Directory? l...File size section 22φ...e First track number section 23...φ...Attribute section 24...Extension section 2511...File section 22a...First track Number recording area 22b/Gaku/Fist bone delete bit Agent Patent attorney Seki Yamashita Figure 3 (A) (73) Figure 4 Ward construction I entrance 99a Figure 5

Claims (1)

[Claims] A directory format characterized in that an area indicating a logical erased file is provided in a first track number section in a directory in which file information regarding file data recorded on an information track is recorded.